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Antineutrino detector for anti. nu. oscillation studies at fission weapon tests and at LAMPF

Description: Two anti ..nu.. oscillation experiments are planned, incorporating large volume (4200 l) liquid scintillation detectors 1) at large distances (450 to 800 m) from fission weapon tests and 2) at 12 to 50 m from LAMPF beam dump where significant anti ..nu../sub e/ events are detected only if some oscillation operates, such as ..nu../sub ..mu../ ..-->.. ..nu../sub e/. Design criteria, detector characteristics, and experimental considerations are given.
Date: January 1, 1980
Creator: Kruse, H.W.; Loncoski, R. & Mack, J.
Partner: UNT Libraries Government Documents Department

Experiment to investigate anti. nu. /sub. mu. /. -->. anti. nu. /sub e/ oscillations at Los Alamos Meson Physics Facility

Description: An experiment, being planned at LAMPF, aims to investigate a possible neutrino oscillation channel, anti ..nu../sub ..mu../ ..-->.. anti ..nu../sub e/. If anti ..nu../sub ..mu../, produced in the LAMPF beam stop, oscillate to anti ..nu../sub e/, then interactions anti ..nu../sub e/ + p ..-->.. e/sup +/ + n, may be detected. A large volume liquid scintillator (4470 liter) emplaced at 33 m from the beam stop, detects e/sup +/ and n, after moderation in the hydrogenous liquid and capture in Gd, loaded into the scintillator. Our anticipated signal rate is currently estimated at 1.67 (sigma m/sup 2/)/sup 2//day assuming full amplitude oscillation. The corresponding counting rate, assuming all anti ..nu../sub ..mu../ have oscillated to anti ..nu../sub e/ at the detector is 1.5/day. Cosmic rates are estimated at 0.033/day. Correlated backgrounds from the beam stop are calculated to be small in comparison to cosmic events, except for reactions of ..nu../sub e/ in Pb. These reactions may be reduced with an Fe shield within the detector. With the above rate, a limit on the sensitivity of our experiment for the value of sigma m/sup 2/ is estimated at 0.12 eV/sup 2/ with 70 days of counting. Detector features, estimated background rates, and sensitivity values are discussed.
Date: January 1, 1981
Creator: Kruse, H.W. & Toevs, J.W.
Partner: UNT Libraries Government Documents Department

Search for neutrino oscillations at the Brookhaven AGS

Description: We report on a search for neutrino oscillations of the type nu/sub ..mu../ ..-->.. nu/sub e/ in a detector located an effective distance of 96m from the neutrino source in the wide band neutrino beam at the Brookhaven AGS. No excess of electron events was observed. The resulting upper limit on the strength of the mixing between nu/sub ..mu../ and nu/sub e/ in the case of large mass difference ..delta..m/sup 2/ = absolute value m/sub 1//sup 2/ - m/sub 2//sup 2/ between the neutrino mass eigenstates m/sub 1/ and m/sub 2/ is sin/sup 2/2..cap alpha.. less than or equal to 3.4 x 10/sup -3/ at 90% CL. The corresponding upper limit for small mass difference is ..delta..m/sup 2/sin2..cap alpha.. < 0.43 eV/sup 2/. 9 refs.
Date: February 20, 1985
Creator: Ahrens, L.A.; Aronson, S.H.; Connolly, P.L.; Gibbard, B.G.; Murtagh, M.J.; Murtagh, S.J. et al.
Partner: UNT Libraries Government Documents Department

Data acquisition for a large neutrino detector

Description: A hierarchical, distributed intelligence data acquisition system which has been used for the past two years in neutrino experiments at Brookhaven National Laboratory is described. Performance characteristics and the nature of problems encountered in bringing the system to maturity are discussed and some generalizations of the experience are suggested.
Date: January 1, 1983
Creator: Ahrens, L.A.; Aronson, S.A. & Connolly, P.L.
Partner: UNT Libraries Government Documents Department

Proposal to assemble a high resolution-electron sensitive-energy flow calorimeter in the NEULAND spectrometer

Description: A ..gamma.. catcher and a liquid scintillation calorimeter module in a simple configuration that is well suited to the investigation of several different neutrino induced processes are described. The variety of neutrino beams now available at Fermilab and synchrotron intensity and energy together with the high resolution calorimeter allow a multiplicity of experiments to be carried out with a single detector configuration.
Date: January 1, 1977
Partner: UNT Libraries Government Documents Department

Comparison of calculated and experimental neutron attenuation and streaming data for fusion reactor design

Description: Integral experiments that measure the neutron and gamma-ray energy spectra resulting from the attenuation of approx. 14 MeV T(D,n)/sup 4/He reaction neutrons in laminated slabs of stainless steel type 304, borated polyethylene, and a tungsten alloy (Hevimet) and from neutrons streaming through a 30-cm-diameter iron duct (L/D = 3) imbedded in a concrete shield have been performed at the Oak Ridge National Laboratory. The facility, NE-213 liquid scintillator detector system, and experimental techniques used to obtain the measured data are described. The two-dimensional discrete ordinates radiation transport codes, calculational models, and nuclear data used in the analysis of the experiments are reviewed.
Date: January 1, 1980
Creator: Santoro, R.T.; Alsmiller, R.G. Jr.; Barnes, J.M. & Chapman, G.T.
Partner: UNT Libraries Government Documents Department

The neutrino program at LAMPF

Description: There are two neutrino experiments that this paper discusses: the first experiment is designed to verify the interference between charged and neutral current amplitudes in {nu}{sub e}- e scattering. The experiment is situated at 90{degree} to the beam stop, and detected recoil electrons from neutrino electron scattering. The experiment is sensitive to recoil electrons from {nu}{sub {mu}}, {nu}{sub e}, {bar {nu}}{sub {mu}} but the cross section for {nu}{sub e} - e scattering is the dominant contribution. The magnitude of this cross section depends on the size of the interference term between charged and neutral current scattering, and the value for this term is {minus}1.07 {plus minus} 0.017 {plus minus} 0.11 to be compared to {minus}1.08 from standard electroweak theory with sin{sup 2}{theta}{sub W} = 0.23. The observation of this interference is unique to this experiment. The second experiment, which is presently finishing data analysis after concluding data taking in 1989, is a search for neutrino oscillations of the type {bar {nu}}{sub mu} {yields} {bar {nu}}{sub e}. The experiment was designed to search for the reaction {bar {nu}}{sub e} + p {yields} e{sup +} + n, which has a large relative cross section compared to that on complex nuclei due to the absence of Pauli Suppression of the reaction on free nucleons producing electrons in the energy range 30--50 MeV in contrast to the dominant background from {nu}{sub e} + {sup 12}C {yields} e{sup +} + {sup 12}N, in which the electron energies are limited to 30 MeV from the Q value of the reaction. 5 refs., 13 figs.
Date: January 1, 1989
Creator: White, D.H.
Partner: UNT Libraries Government Documents Department

Measuring the quark contribution to the proton spin through. nu. p yields. nu. p

Description: The LSND (Liquid Scintillator Neutrino Detector) experiment will be performed at LAMPF in the next several years. The main goal of the experiment is to search for {nu}{sub {mu}}-{nu}{sub e} oscillations with high sensitivity; however, an increasingly important by-product of this search is to measure {nu}p {yields} {nu}p elastic scattering and determine the strange quark contribution, {Delta}s, to the spin of the proton. With the 800-MeV proton energy of LAMPF, neutrinos are produced from pion decay-in-flight with an average energy of about 150 MeV. This energy is sufficiently high so that the {nu}p {yields} {nu}p cross section is large and is sufficiently low so that the low Q{sup 2} approximation (Q{sup 2} {much lt} m{sub p}{sup 2}) is valid and the cross section can be expressed in a simple form dependent upon {Delta}s as the only unknown. LAMPF with its 1-mA proton intensity is, therefore, an ideal accelerator to perform this measurement. 12 refs., 7 figs., 2 tabs.
Date: January 1, 1991
Creator: Louis, W.C.
Partner: UNT Libraries Government Documents Department

Neutron spectrum measurements for radiation protection purposes

Description: The energy spectra of low-intensity neutron sources used for calibrating personnel neutron dose-rate meters and dosimeters and for characterizing the neutron fields to which personnel are exposed were measured. Several detector-analyzer systems that will measure in the energy range 50 keV to 20 MeV at intensities from 10/sup -1/ to 10/sup 5/ n/cm/sup 2/-s are described. The systems include NE213 and stilbene organic scintillators as well as H/sub 2/, /sup 3/He, and CH/sub 4/ proportional counters. Also described are pulse-height analysis and pulse-shape discrimination systems. An unfolding code, NUTSPEC, reduces the pulse-height data to an absolute differential neutron flux phi(E) for the above detectors. The code uses a derivative unfolding method for the scintillation detectors, and for the proportional counters it calculates a response matrix and uses an iterative unfolding method to determine phi(E). The unfolded flux distribution combined with published conversion factors produces differential neutron dose-equivalent and kerma rates. Spectral segments obtained with different detectors from several measurements merge into a single differential flux spectrum over the range 50 keV to 20 MeV, together with the corresponding differential kerma and neutron dose-equivalent distributions. Also reported are spectrum measurements near /sup 252/Cf and /sup 238/PuBe sources with various moderators.
Date: February 21, 1978
Creator: Slaughter, D.R.; Rueppel, D.W. & Fuess, D.A.
Partner: UNT Libraries Government Documents Department

Liquid-helium scintillation detection with germanium photodiodes

Description: Special high-purity germanium photodiodes have been developed for the direct detection of vacuum ultraviolet scintillations in liquid helium. The photodiodes are immersed in the liquid helium, and scintillations are detected through one of the bare sides of the photodiodes. Test results with scintillation photons produced by 5.3-MeV ..cap alpha.. particles are presented. The use of these photodiodes as liquid-helium scintillation detectors may offer substantial improvements over the alternate detection method requiring the use of wavelength shifters and photomultiplier tubes.
Date: May 1, 1982
Creator: Luke, P.N.; Haller, E.E. & Steiner, H.M.
Partner: UNT Libraries Government Documents Department

Experimental investigations in particle physics at intermediate energies. [Physics Dept. , Temple Univ]

Description: The major emphasis of this project continues to be on fundamental symmetries and parameters of the Standard Model. A test of a quark model prediction was also done. The projects in the current period have been the following: LSND, a neutrino oscillation experiment at LAMPF; E791, a search for the decays K{sub L}{sup 0} {yields} {mu}e and K{sub L}{sup 0} {yields} ee; E871, tests and preparations for an upgrade proposal; and E888, a search for the H dibaryon. The LSND (Large Scintillator Neutrino Detector) is under construction at this time. Progress in the construction schedule has been accelerated with the expectation of being ready to accept beam in March 1993. The automated system for testing photomultiplier tubes is in full production, and should be able to certify a fun complement of tubes for installation by October 1992. Results of an earlier LAMPF experiment, E764, on the interaction of muon neutrinos with carbon nuclei have been submitted for publication. A thorough 'blind' analysis of the E791 data set has just been brought to completion. Final results for the upper limits (90% C.L.) on the branching ratios for the decays K{sub L}{sup 0} {yields} {mu}e and K{sub L}{sup 0} {yields} ee are 3.3 {times} 10{sup {minus}11} and 4.1 {times} 10{sup {minus}11}, respectively. The final result for the branching ratio for K{sub L}{sup 0} {yields} {mu}{mu} from all the data (720 events) is (7.0 {plus minus} 0.4 {plus minus} 0.2) {times} 10{sup {minus}9}. The potential of the E791 detector for rare K decays has reached its limit. Before disassembly it was used to mount a search (E888) for a possible long-lived six-quark state, the H. At the same time studies have been made of an upgraded version of the experiment (E871) that will make use of a portion of the existing apparatus.
Date: July 12, 1992
Creator: Auerbach, L.B.; Highland, V.L.; McFarlane, K.W. & Kettell, S.H.
Partner: UNT Libraries Government Documents Department

Experimental particle physics. [Dept. of Physics, Drexel Univ]

Description: The goals of this research are the experimental testing of fundamental theories of physics beyond the standard model and the exploration of cosmic phenomena through the techniques of particle physics. We are working on the MACRO experiment, which employs a large-area underground detector to search fore grand unification magnetic monopoles and dark matter candidates and to study cosmic ray muons as well as low- and high-energy neutrinos; the Chooz experiment to search for reactor neutrino oscillations at a distance of 1 km from the source; a new proposal (the Perry experiment) to construct a one-kiloton liquid scintillator in the Fairport, Ohio underground facility IMB to study neutrino oscillations with a 13 km baseline; and development of technology for improved liquid scintillators and for very-low-background materials in support of the MACRO and Perry experiments and for new solar neutrino experiments.
Date: September 1, 1992
Creator: Steinberg, R.I. & Lane, C.E.
Partner: UNT Libraries Government Documents Department

High Energy Physics Program at Texas A and M University

Description: The high energy physics program has continued its experimental activities over. In CDF, the Texas A M group has led an effort to design an upgrade for the silicon vertex detector, and is currently working with the rest of the collaboration on the next major data taking run. In MACRO, work was done on the development of the final version of the wave form digitizing system being implemented for the entire scintillator system. This work is nearing completion, and the system is expected to be up and running on the detector by summer 1993. Work was done within the SDC group to develop gas microstrip chambers for use in precision tracking at the SSC, and in the GEM group, toward the development of a suitable forward calorimeter design. The theoretical high energy physics program has continued the study of a very successful string-derived model that unifies all known interactions: flipped SU(5), which is the leading candidate for a TOE. Work has also continued on some generalizations of the symmetries of string theory, known as W algebras. These are expected to have applications in two-dimensional conformal field theory, two-dimensional extensions of gravity and topological gravity and W-string theory.
Date: November 1, 1992
Partner: UNT Libraries Government Documents Department

Non-accelerator particle physics

Description: The goals of this research are the experimental testing of fundamental theories of physics such as grand unification and the exploration of cosmic phenomena through the techniques of particle physics. We are working on the MACRO experiment, which employs a large area underground detector to search for grand unification magnetic monopoles and dark matter candidates and to study cosmic ray muons as well as low and high energy neutrinos: the {nu}IMB project, which seeks to refurbish and upgrade the IMB water Cerenkov detector to perform an improved proton decay search together with a long baseline reactor neutrino oscillation experiment using a kiloton liquid scintillator (the Perry experiment); and development of technology for improved liquid scintillators and for very low background materials in support of the MACRO and Perry experiments and for new solar neutrino experiments. 21 refs., 19 figs., 6 tabs.
Date: September 1, 1991
Creator: Steinberg, R.I. & Lane, C.E.
Partner: UNT Libraries Government Documents Department

A proposal to search for neutrino oscillations with high sensitivity in the appearance channels. nu. sub. mu. yields. nu. sub e and. nu. sub. mu. yields. nu. sub e

Description: An experiment is proposed to search concurrently for {nu}{sub {mu}} {yields} {nu}{sub e} and {bar {nu}}{sub {mu}} {yields} {bar {nu}{sub e} oscillations with high sensitivity at LAMPF. The detector consists of a tank with 200 tons of dilute liquid scintillator with 850 10-in. photomultiplier tubes mounted on the inside tank covering 28% of the surface. Both Cerenkov light and scintillation light will be detected. The tank will reside inside the existing E645 veto shield and the experiment will make use of the present A6 beam-stop neutrino source. After two years of data collection, 90% confidence level limits on {bar {nu}{sub mu}}({nu}{sub {mu}}) {yields} {bar {nu}}{sub e}({nu}{sub e}) mixing strengths of 2.7(2.7) {times} 10{sup {minus}4} can be obtained for all {Delta}m{sup 2} > 1 eV{sup 2}. Similarly, for maximal mixing the 90% C.L. limits on {Delta}m{sup 2} are 1.7(4.0) {times} 10{sup {minus}2}. This experiment will, therefore, provide the world's best terrestrial limits on {nu}{sub {mu}} {yields} {nu}{sub e}} oscillations. Other physics to be obtained includes measurements of the charged current reactions {nu}{sub e}C {yields} e{sup {minus}}N and {nu}{sub {mu}}C {yields} {mu}{sup {minus}}N, of the inelastic neutral current reaction {nu}C {yields} {nu}C* (15.11- MeV {gamma}), and a search for the rare decays {pi}{sup 0} {yields} {nu}{bar {nu}} and {eta} {yields} {nu}{bar {nu}}.
Date: August 1, 1990
Creator: Lu, X-Q.; Yodh, G. (California Univ., Irvine, CA (USA)); Fung, S.Y.; Kang, J.H.; Shen, B.C.; VanDalen, G.J. (California Univ., Riverside, CA (USA)) et al.
Partner: UNT Libraries Government Documents Department

Monitoring tritium in air containing other radioactive gases

Description: A brief survey is presented of methods that have been developed for active tritium monitoring that may be applied to measure tritium concentrations in air containing /sup 13/N, /sup 16/N, and /sup 41/Ar produced by D-T neutrons. Included are instruments that employ current subtraction to achieve discriminations and others that selectively remove atmospheric water vapor from stream of activated air.
Date: September 1, 1982
Creator: Jalbert, R.A.
Partner: UNT Libraries Government Documents Department

Aqueous effluent tritium monitor development

Description: The development of a low-level tritium monitor for aqueous effluents has explored several potential techniques. In one method, a water-immiscible liquid scintillation cocktail was ultrasonically mixed with an aqueous sample to form a water-cocktail dispersion which was analyzed by liquid scintillation spectrometry. The organic cocktail could then be reused after phase separation. Of the cocktails tested, the highest tritium detection efficiency (7%) was determined for a toluene-based cocktail. In another technique, the response of various solid scintillators (plastic beads, crushed inorganic salts, etc.) to tritium solutions was measured. A 2% tritium detection efficiency was observed for the most efficient solid scintillators tested. In a third method, a large surface area detector was constructed from thin fibers of plastic scintillator. This detector had a 0.1% intrinsic tritium detection efficiency. While sensitivities of {approximately}25 kBg/L of tritium for a short count have been attained using several of these techniques, non can reach the environmental level of <1 kBg/L in aqueous solutions.
Date: January 1, 1991
Creator: Hofstetter, K.J. & Wilson, H.T.
Partner: UNT Libraries Government Documents Department

Investigation of Cerenkov counting of environmental strontium-90

Description: A typical liquid scintillation counter was evaluated for detection of low levels of /sup 90/Sr-Y. A blank of about 5 cpm and /sup 90/Y efficiency of 42% were obtained for 20-ml samples. The corresponding minimum detectable concentration for a 100-minute count is 0.03 pCi/ml, so that measurement of water samples can readily be made at the maximum permissible concentration for /sup 90/Sr, 0.3 pCi/ml. The efficiency for /sup 90/Sr is less than 0.4%, 1.4% for /sup 137/Cs, and less than 0.04% for gamma-emitting /sup 85/Sr, a useful tracer. Some data for /sup 90/Y efficiencies and blanks are given for other liquid scintillation counters. Chemical treatments are necessary in some cases to concentrate /sup 90/Sr-Y, to remove colored substances which cause quenching, or to eliminate interfering radionuclides. However, the manipulations need not be as elaborate as in conventional radiochemical analysis methods for /sup 90/Sr. Ferric ion (yellow) quenches at the 5 ppM level, but the interference can be eliminated by adding a reducing agent. The Rn daughter /sup 214/Bi, an interfering radionuclide, disappears by decay in 2-3 hours after removal of Rn by sweeping with air or gas. Concentration-separation methods studied have included precipitation and ion exchange.
Date: January 1, 1979
Creator: Reynolds, S.A. & Eldridge, J.S.
Partner: UNT Libraries Government Documents Department

Development of neutron multiplicity counters for safeguards assay

Description: This paper reports on the development of a new generation of neutron multiplicity counters for assaying impure plutonium. The new counters will be able to obtain three measured parameters from the neutron multiplicity distribution and will be able to determine sample mass, multiplication, and (..cap alpha..,n) reaction rate, making it possible to obtain a more matrix-independent assay of moist or impure materials. This paper describes the existing prototype multiplicity counters and evaluates their performance using assay variance as a figure of merit. The best performance to date is obtained with a high-efficiency, low die-away-time thermal neutron counter with shift-register electronics. 10 refs., 2 figs., 4 tabs.
Date: January 1, 1989
Creator: Ensslin, N.
Partner: UNT Libraries Government Documents Department

Analysis of low energy beta-emitters

Description: A survey was made of the instruments used for the determination of low energy beta radioactivity. Techniques commonly used are gas flow proportional counting, liquid scintillation counting, solid scintillation counting, and internal ionization chamber counting, solid state detector counting, and radiochemical separation followed by counting using one of the preceeding techniques. The first four techniques were examined and compared with each other. The sensitivities of the techniques were compared on the basis of the detection limits quoted for instruments described in the technical and reviewed literature. The detection limits were then related to the occupational and public individual maximum levels for air and water. Attention is focused primarily on the continuous monitoring of air for /sup 3/H and /sup 85/Kr, a medium energy ..beta..-emitter. It is clear that several continuous air monitoring instruments are readily available for measuring low energy ..beta.. concentrations, even in presence of certain other activity, at occupational levels. However, these instruments do not typically have sensitivities comparable to the public individual levels. Moreover, their capabilities for giving results in real time and for differentiating among the radionuclides actually present is limited.
Date: October 1, 1979
Creator: Murphy, D.L.
Partner: UNT Libraries Government Documents Department

Measurement of tritium permeation through resistant materials near room temperature

Description: To measure tritium permeation through low-permeability materials at 50 to 170/sup 0/C, we use highly-sensitive liquid scintillation counting to detect the permeating tritium. To validate our method, we conducted extensive experiments with copper, for which much data exists for comparison. We report permeability of tritium through copper at 50, 100, and 170/sup 0/C, and discuss details of the experimental technique. Further plans are outlined. 15 refs., 5 figs., 1 tab.
Date: January 1, 1985
Creator: Maienschein, J.; DuVal, V.; McMurphy, F.; Uribe, F.; Musket, R. & Brown, D.
Partner: UNT Libraries Government Documents Department